The invention relates to a pump arrangement, in particular magnetic clutch pump arrangement. The pump arrangement has an interior space formed by a pump casing of the pump arrangement, a containment can which hermetically seals off a chamber surrounded by said containment can with respect to the interior space formed by the pump casing, an impeller shaft which can be driven in rotation about an axis of rotation, an impeller which is arranged on one end of the impeller shaft, an inner rotor arranged on the other end of the impeller shaft, having a drive motor, having a drive shaft which can be driven rotatably about the axis of rotation by the drive motor, and an outer rotor which is arranged on the drive shaft and which interacts with the inner rotor. The outer rotor has a hub with a hub inner surface formed by a passage bore, in which hub inner surface there is formed an axial groove which extends parallel to the axis of rotation and which interacts with a feather key inserted into a feather key groove of the drive shaft.
German patent document no. DE 84 36 638 U1 has disclosed a pump arrangement of said type. Despite a tight sliding fit of the outer magnet carrier on the drive shaft, the fit clearance that still exists has the effect that the outer magnet carrier tilts relative to the drive shaft, whereby, as the drive shaft is driven in rotation, the outer magnet carrier exhibits a wobbling movement, which can lead to damage to the containment can or to other parts within the pump arrangement. If the fit is selected to be too tight, mounting is possible only with a heating action, and dismounting is possible only with the use of special tools.
It is the object of the invention to provide a pump arrangement which permits clearance-free mounting, which can be performed without the use of special tools, of the outer rotor, which bears the magnets, onto the drive shaft of a drive motor.
The object of the invention is achieved in that at least one radially encircling first groove and at least one radially encircling second groove are formed in the hub inner surface, wherein a tolerance ring is arranged at least in two of the grooves.
It is preferable for a tolerance ring to be arranged in at least one or more of the first grooves and in one or more of the second grooves.
It is expedient for a tolerance ring to be arranged in one of the first grooves and for a tolerance ring to be arranged in one of the second grooves.
In one refinement of the invention, it is proposed that the pump arrangement is of a block-type design, that is to say the pump casing is connected to the motor casing. In this way, no baseplate, or a baseplate of relatively small size, is required for the pump arrangement. Furthermore, a mechanical coupling can be dispensed with. Furthermore, expenditure of effort that is otherwise required for alignment purposes is omitted.
Adverse true running characteristics of the outer rotor which is driven rotatably by way of the drive shaft are avoided if at least one first groove is formed in a region of the hub inner surface which is situated substantially between the center of the hub and the first carrier element in the axial direction, and/or at least one second groove is formed in a region of the hub inner surface which extends substantially from the center of the hub to a point close to that end of the hub which is situated opposite the first carrier element.
What has proven to be particularly advantageous is a refinement in which the outer shell surface of the hub is of smooth form. By virtue of bores, discontinuities or slots in or on the outer shell surface of the hub being omitted, it is made possible for the outer rotor to be slid onto the drive shaft without damage being caused to seal elements arranged in said region.
For simple mounting and dismounting of the hub and drive shaft, there is provided a threaded bore which is formed in the outer rotor in the region of the first carrier element.
With regard to the simple mounting and dismounting of hub and drive shaft, it is provided here that the threaded bore has a larger diameter than a threaded blind bore provided in the drive shaft.
In a further advantageous refinement, the tolerance rings are dimensioned such that they do not extend into the feather key groove which receives the feather key.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.